Solid Secondary Battery Electrolyte Layers for Lower Interfacial Resistance
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Solution Overview
Problem
Lithium secondary batteries with liquid electrolytes are prone to fires and explosions due to short circuits, necessitating the development of solid electrolyte-based batteries for improved safety, but these face challenges in cycling performance and interfacial resistance.
Innovation Solution
A solid secondary battery design incorporating high-viscosity organic electrolytes between the cathode and anode layers, and within the solid electrolyte layer, to reduce interfacial resistance and accommodate volume changes during charging and discharging, thereby enhancing cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte is used instead of liquid electrolyte, then safety is improved, but cycling performance deteriorates
Solution Approach 1:
The patent introduces an organic electrolyte layer as an intermediary between the solid electrolyte and the electrodes. This organic electrolyte acts as a mediator that facilitates ion transport at the interface while the solid electrolyte maintains its safety advantages. The organic electrolyte fills in the gaps and improves contact between the solid electrolyte and electrodes, thereby enhancing cycling performance without compromising safety.
Solution Approach 2:
The patent creates a composite electrolyte system combining solid electrolyte and organic electrolyte in a layered structure. The solid electrolyte provides safety and structural stability, while the organic electrolyte provides excellent ion conductivity and flexibility. This composite approach allows the battery to achieve both safety improvement and enhanced cycling performance by leveraging the complementary strengths of both electrolyte types.
2Object-affected harmful factors
If solid electrolyte is used instead of liquid electrolyte, then fire risk is reduced, but interfacial resistance increases
Solution Approach 1:
The organic electrolyte layer serves as an intermediary that reduces interfacial resistance between the solid electrolyte and electrodes. It improves the physical contact and ionic coupling at the interfaces, thereby lowering resistance without affecting the fire safety provided by the solid electrolyte.
Solution Approach 2:
The patent changes the physical state and properties of the electrolyte system by introducing an organic electrolyte with appropriate viscosity and conductivity parameters. This parameter adjustment optimizes the interfacial characteristics and reduces resistance while maintaining the safety benefits of the solid electrolyte structure.
3Stability of the object's composition
If solid electrolyte is used, then battery stability is improved, but volume change accommodation deteriorates
Solution Approach 1:
The patent segments the electrolyte system into distinct solid and organic electrolyte layers. The solid electrolyte layer provides structural stability and compositional integrity, while the organic electrolyte layer provides flexibility and adaptability to accommodate volume changes during charging and discharging cycles.
Solution Approach 2:
The composite electrolyte structure combines the stability of solid electrolyte with the flexibility of organic electrolyte. This allows the battery to maintain compositional stability while adapting to volume changes, as the organic layer can deform and reconfigure to accommodate electrode expansion and contraction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of high-viscosity organic electrolytes decreases interfacial resistance, suppresses defect formations, and improves the battery's high-rate capability and lifespan, leading to enhanced cycling performance and safety.
Implementation Method 1
the liquid electrolyte having a viscosity of 10 cps or more at 25° C. and 1 atm
Data Source
AI summary
A solid secondary battery includes a cathode layer, an anode layer, and a solid electrolyte layer between the cathode layer and the anode layer and further includes a first organic electrolyte between the cathode layer and the solid electrolyte layer, a second organic electrolyte between the anode layer and the solid electrolyte layer, a third organic electrolyte in the solid electrolyte layer, or any combination thereof, wherein the first organic electrolyte, the second organic electrolyte, and the third organic electrolyte each independently include a polymer electrolyte, a liquid electrolyte, or any combination thereof, the liquid electrolyte having a viscosity of 10 cps or more at 25° C. and 1 atm, wherein the cathode layer includes a cathode current collector and a cathode active material layer on at least one surface of the cathode current collector, the cathode active material layer including a Li2S-containing composite.